mirror of
https://github.com/prometheus/prometheus.git
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102 lines
2.2 KiB
Go
102 lines
2.2 KiB
Go
/*
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Copyright 2016 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package workqueue
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import (
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"context"
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"sync"
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utilruntime "k8s.io/apimachinery/pkg/util/runtime"
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)
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type DoWorkPieceFunc func(piece int)
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type options struct {
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chunkSize int
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}
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type Options func(*options)
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// WithChunkSize allows to set chunks of work items to the workers, rather than
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// processing one by one.
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// It is recommended to use this option if the number of pieces significantly
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// higher than the number of workers and the work done for each item is small.
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func WithChunkSize(c int) func(*options) {
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return func(o *options) {
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o.chunkSize = c
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}
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}
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// ParallelizeUntil is a framework that allows for parallelizing N
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// independent pieces of work until done or the context is canceled.
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func ParallelizeUntil(ctx context.Context, workers, pieces int, doWorkPiece DoWorkPieceFunc, opts ...Options) {
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if pieces == 0 {
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return
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}
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o := options{}
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for _, opt := range opts {
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opt(&o)
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}
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chunkSize := o.chunkSize
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if chunkSize < 1 {
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chunkSize = 1
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}
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chunks := ceilDiv(pieces, chunkSize)
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toProcess := make(chan int, chunks)
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for i := 0; i < chunks; i++ {
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toProcess <- i
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}
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close(toProcess)
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var stop <-chan struct{}
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if ctx != nil {
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stop = ctx.Done()
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}
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if chunks < workers {
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workers = chunks
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}
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wg := sync.WaitGroup{}
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wg.Add(workers)
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for i := 0; i < workers; i++ {
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go func() {
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defer utilruntime.HandleCrash()
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defer wg.Done()
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for chunk := range toProcess {
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start := chunk * chunkSize
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end := start + chunkSize
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if end > pieces {
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end = pieces
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}
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for p := start; p < end; p++ {
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select {
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case <-stop:
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return
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default:
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doWorkPiece(p)
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}
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}
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}
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}()
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}
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wg.Wait()
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}
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func ceilDiv(a, b int) int {
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return (a + b - 1) / b
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}
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